Detersive systems have been used for many years in many cleaning environments including the laundry, warewashing, hard surface cleaning, and other applications. Typically, detersive systems are concentrates comprising mixtures of cleaning ingredients that when mixed with water form a cleaning medium or use composition. Service water, containing some concentration of hardness ions, supplied by local water utilities is most commonly used in making the use composition. Hardness ions are typically undesirable in conjunction with detersive systems since they interfere in the soil removal mechanism. The quality of service water varies from place to place throughout the country and can vary in hardness and can vary in the hardness components. Hardness typically comprises metal ions including calcium, magnesium, iron, manganese, and other typically divalent or trivalent metal cations depending on the source of the water. The presence of hardness cations in service water can substantially reduce the detersive action or effectiveness of a detersive system, can result in the incomplete cleaning of laundry, dishware, hard surfaces, and other soiled items or surfaces and can leave films or scale comprising the hardness cation and/or components of the detersive system.
A great deal of attention in recent years has been given to the components of detersive systems that reduce the effects of the hardness components. Common hardness sequestering agents comprise inorganic chemicals such as a condensed phosphate compound and a zeolite, and organic sequestrants such as EDTA, organic phosphonates and organic phosphinates. Such agents are effective in treating hardness in service water by a chemical reaction which keeps the ions in the aqueous bulk detersive system but reduces the hardness effect of the ions on the detersive systems. These agents can be effective but provide both economic and ecological disadvantages. Other hardness sequestering agents have been proposed in the prior art but have encountered economic, environmental, or compatibility problems in detersive systems.
Accordingly, a substantial need exists for hardness treating or softening agents that can be used in detersive systems at low concentration which can effectively soften service water through a mechanism of removing hardness ions from aqueous media used in detersive systems with no increase in cost, adverse environmental impact, or compatibility problems in detersive systems.